The Samples.3mf file is just for display. Each size base is in its own file (using the Download STL option).

This is a set of Gridfinity bases 1x1 through 5x5 with the magnet holes sized to 6.08mm x 2.05mm for press fitting. The hole underneath is for easy removal. The connection hole diameter is sized at 1.79mm for a decent fit with Bambu filament.

The magnets I use: https://www.amazon.com/gp/product/B09XK9ZMVQ/